Abstract
Subcellular distribution of 5-hydroxytryptamine (5-HT) in rabbit brain stem was investigated by the technique of differential and density-gradient centrifugation. The present study confirmed the finding that 5-HT was principally found in crude mitochondrial fraction (P2). Further subfractionation of P2-fraction revealed that the high concentration of 5-HT was found in P2B- and P2V-fraction although considerable amount of 5-HT was also found in P2D- and P2S-fraction. Electron microscopic examination showed that P2- and P2V-fraction consisted largely of nerve-ending particles and synaptic vesicles, respectively.
